on E shore of Frederick Sound, 2 mi. E of McDonald I. and 8 mi. of Petersburg, Coast Mts.
Named in 1887 by Lieutenant Commander C. M. Thomas, U.S. Navy (USN).
California Boulder Patch, Colorado Reef, Prolewy Rocks,
Bays:Bock Bight, Brown Cove, Halfmoon Anchorage, Icy Cove, Ideal Cove, Long Pond, Scow Bay, Thomas Bay,
Capes:Point Agassiz, Point Agassiz Peninsula, Anchor Point, Bayou Point, Blind Point, Blunt Point, Cosmos Point, Danger Point, False Island Point, Finger Point, Frederick Point, Green Point, Island Point, Mountain Point, Prolewy Point, Rock Point, Spruce Point, Spurt Point, Turn Point, Vexation Point, Wind Point, Wood Point,
Channels:Petersburg Bar Range, Wrangell Narrows,
Cities:Cliffs:Dams:Petersburg Dam, Petersburg Lower Reservoir Dam,
Fictional Places:Flats:Boulder Flats, North Flat, South Flat,
Glaciers:Islands:Big Bowlder, Blind Island, Bush Top Island, Camp Island, Coney Island, Grassy Island, Green Rocks, Hidden Island, McDonald Islands, Pocket Island, Prolewy Rocks, Ruth Island, Sasby Island, Sukoi Islets, Woody Island,
Lakes:Brown Cove Lake, Ess Lake, Falls Lake, Green Rocks Lake, Petersburg Reservoir, Ruth Lake, Swan Lake,
Mountains:Church Peak, Cosmos Peak, Fighting John Peak, Foote Peak, Horn Mountain, Jenkins Peak, Narrows Peak, Petersburg Mountain, Pin Peaks, Pirate Peak, Porter Peak, Rodgers Peak, Saw Peaks, Survey Mountains, Thunder Mountain, Waterfall Peak,
Mountain Ranges:Ridges:Rivers:Streams:Bear Creek, Cascade Creek, Clear Creek, Colorado Creek, Crystal Creek, Delta Creek, Falls Creek, Fivemile Creek, Japanese Creek, Moonshine Creek, Taain Creek, Twin Creek,
Cities:Routes:Colp Lake Trail, Ideal Cove Trail, Petersburg Lake Trail, Raven Trail, Ruth Lake Trail, Spurt Point Lake Trail, Swan Lake Trail,
Valleys:Cities: